Approximate Dimensions for Chain & Fittings Commonly used marine chain with a central stud for extra weight and to prevent elongation under extreme loads.Beaver Engineering offers Grade 2 and Grade 3 Approximate Dimensions for Chain & Fittings Approximate Dimensions for Chain & FittingsD = Nominal Diameter of Chain Common Link Enlarged Link End Link Normal Adaptor Piece Swivel W/4 Link Forerunner Joining Shackle Type Kenter Joining Shackle Type D Anchor Shackle Type D Swivel Shackle Type A Swivel Slim Connectors We Provide The Best Service In The Industry